1. Field of the Invention
The present invention relates to a sunshade system, and specifically to a sunshade system that has a blind sheet for covering a window of a vehicle to shade sunlight.
2. Description of Related Art
When a vehicle is parked under the burning sun, and sunlight enters an occupant compartment of the vehicle, the temperature of the occupant compartment rises. When an occupant returns and enters the occupant compartment of the vehicle, the occupant experiences hot sensation and feels uncomfortable. In such a state, when an air conditioning system is actuated, hot air is blow from the air conditioning system toward the occupant at the beginning of the operation of the air conditioning system, so that the occupant feels uncomfortable. Also, in such a case, the time required to lower the temperature of the occupant compartment to a desired comfortable level is relatively long. Furthermore, when the temperature needs to be rapidly decreased, the conditioning air, which is blown from the air conditioning system, needs to be increased. This results in an increase in the energy consumption.
Previously, a separate sunshade is commonly used. The sunshade is placed to an occupant compartment side of a front window to shade the sunlight, which enters the occupant compartment. The sunshade is simply left along the window without connecting it to the window or is connected to the window by, for example, sucking disks. However, the separate sunshade needs a space to store it when the sunshade is not in use. Also, the separate sunshade diminishes the appearance of the interior of the occupant compartment.
To address the above disadvantage, Japanese Unexamined Patent Publication No. 2003-182358 discloses a sunshade system. In this sunshade system, a blind sheet is wound at a lower end of a side window (door window) of a vehicle and is extended from the lower end of the side window toward an upper end of the side window. In such a case, it cannot serve as a sun visor. In order to shade the sunlight, which enters an occupant compartment of the vehicle, the blind sheet needs to be extended generally to the upper end of the side window. At this time, a lower part of the side window is covered by the blind sheet, and thus an occupant cannot see the outside of the vehicle through the side window.
Furthermore, Japanese Unexamined Patent Publication No. 2000-52763 proposes a sunshade system, which is installed in a vehicle. In this sunshade system, a blind sheet, which shades the sunlight by covering a front window of a vehicle, is extended or retracted by rotating a winding apparatus. The winding apparatus linearly extends near a top edge of an occupant compartment side of the window. Even in a case where an air bag is place in a dashboard in front of a front passenger seat, the winding apparatus does not interfere with the air bag since the winding apparatus is arranged at the upper edge of the window. Therefore, it is possible to provide the sunshade system to the front window.
In Japanese Unexamined Patent Publication No. 2000-52763, a base end of the rectangular blind sheet is secured to the winding apparatus, and a tubular stay is connected along a free end of the blind sheet. Left and right slide shafts are inserted in left and right ends of the stay, so that the slide shafts are slidable in the axial direction of the stay. A runner is connected to an outer end of each slide shaft.
Left and right guide rails are arranged along front pillars, respectively, of the vehicle. The runners are slidable along the guide rails, respectively. A flexible wire member, which has a lower end connected to the runner, is received in each guide rail. The flexible wire member is driven by a drive apparatus to move along the guide rail.
In the sunshade system disclosed in Japanese Unexamined Patent Publication No. 2000-52763, when the drive apparatus is driven to move each flexible wire member along the corresponding guide rail, the runners, the slide shafts and the stay are moved along the guide rails to extend or retract the blind sheet.
In general, the front window of the vehicle is shaped into a trapezoidal shape, which has a width that increases toward its lower end. Thus, in the above sunshade system, a space between the guide rails increases toward lower ends of the guide rails. Therefore, in the sunshade system, the slide shafts are slid in conformity with the space between the guide rails, so that the entire length of the stay and the slide shafts is adjusted.
In the prior art sunshade system disclosed in Japanese Unexamined Patent Publication No. 2000-52763, whenever the sunshade system is needed, the sunshade system is operated, so that the blind sheet is extended to cover the window and thereby to shade the sunlight. Furthermore, unlike the sunshade, which is left along the window without connecting it to the window or is connected to the window by, for example, the sucking disks, the above prior art sunshade system does not require a large storage space. In addition, the above prior art sunshade system is integrated into the vehicle body, so that it does not diminish the appearance of the interior of the occupant compartment.
However, the front window is shaped into the trapezoidal shape, which has the width that increases toward its lower end. Thus, when the above sunshade system is fully extended, generally triangular spaces, which are uncovered by the blind sheet, are left on the left and right sides of the window, and the sunlight enters the occupant compartment through the uncovered spaces to cause an increase in the temperature in the occupant compartment.
Furthermore, the front window of the vehicle is curved such that a widthwise center of the front window is convexed toward a front end of the vehicle in comparison to the left and right lateral sides of the front window. Also, a rear window of the vehicle is curved such that a widthwise center of the rear window is convexed toward a rear end of the vehicle in comparison to the left and right lateral sides of the rear window. Thus, when a linear roll of the winding apparatus, around which the blind sheet is wound, is installed to the roof side of the vehicle, the roll needs to be spaced away from the front window toward the rear end of the vehicle in the case of installing it to the front window or needs to be spaced away from the rear window toward the front end of the vehicle in the case of installing it to the rear window. However, in order to avoid interference with, for example, a sunroof and to provide a wide space in the occupant compartment, it is desirable to place the roll near the corresponding window as close as possible.
Furthermore, in the above prior art sunshade system disclosed in Japanese Unexamined Patent Publication No. 2000-52763, the blind sheet is extended or retracted by the drive apparatus. Thus, when the drive apparatus fails or malfunctions in the fully extended state of the blind sheet, the blind sheet cannot be retracted.